Idling device featuring actuatorcontrolled spring



Aug. 27, 1957 w. E. MGFARLAND 2,804,553

IDLING DEVICE FEATURING ACTUATOR-CONTROLLED SPRING Filed Oct. 5, 1955 3Sheets-Sheet l IWILUAM E.N\ FAP\LAND INVENTOR;

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v Aug. 27, 1957 w. E. MOFARLAND 2,804,553

IDLING DEVICE FEATURING ACTUATOR-CONTROLLED SPRING Filed Oct. 5, 1955 3Sheets-Sheet 2 FIG. 2

W|LL\AN\ EM: FARLAND INVEN TOR.

1957 w. E.' MCFARLAND 2,804,553

IDLING DEVICE FEATURING ACTUATOR-CONTROLLED SPRING Filed 001;. 5, 1955 3Sheets-Sheet 3 WILLIAM E. MCFARLAND INVENTOR. W62:

United States Patent 6 IDLING DEVICE FEATURING ACTUATOR- CUNTROLLEDSPRING William E. McFarland, Nutley, N. J.

Application (Pctober 5, 1955, Serial No. 538,550

4 Claims. (Cl. 290-40) This invention deals with an idling device forenginegenerator sets employing internal combustion engines wherein aload-responsive relay controls an electromagnetic actuator which, inturn, controls the effect of a throttle-closing spring in a mannerestablishing a slow governed engine speed at the no load condition(idling condition) and the required faster governed engine speed whenelectric load is connected.

In the past, idling devices have been proposed in which the engine speedis continuously under the control of the primary mechanical(centrifugal) governor, it being necessary, in some manner, to insurethat the centrifugal governor operates under relatively light springbias during the period without load, and under full normal spring biasduring the period when the electrical load is connected. Arrangementssuggested heretofore intended to achieve this purpose, involve certainbasic and undesirable alterations of the centrifugal governor itself,such as substituting two light-acting loading springs for the usual fullstrength loading spring. Idling devices of these types have been ratherdifiicult to install and to adjust, especially if the device is addedafter the generator set has left the factory. Furthermore, in most ofthe suggested structures, it is not conveniently possible to makeadjustment to raise or lower the governed idling speed becauseadjustment of the higher speed operation is not independent of theadjustment of slow speed operation. A further disadvantage of suchstructures is that they have not been suited for using generated currentas the motive energy when the necessary change in spring biasing of thecentrifugal governor is effected.

Usually, the only fully practical motive energy for operating an idlingdevice is an electromagnetic actuator energized by generated currentrather than by a battery. It is the principal object of the presentinvention to provide an arrangement, including an electromagneticactuator energized by shunt connection with one generator of thegenerator set, to control the action of a simple spring which isinterconnected with the actuator and the governed throttle system, sothat said spring opposes the conventional governor loading spring duringperiods without electrical load and does not oppose the loading springduring the period when electrical load is in effect.

In broad aspect, the present invention embodies the following elements:

1 1. An engine-generator set having a governed throttle system,including a centrifugal governor connected to the throttle, the governorhaving a loading spring of such force as to enable regulation of thethrottle for predetermined load speed operation under varying load;

2. A normally effective throttle-closing spring which opposes thegovernor loading spring to reduce effectively the spring loading of thecentrifugal governor and thereby to enforce, when required, a governedslow (idling) speed;

3. An electromagnetic actuator, energizable by. shunt connection withgenerated current and connected to the throttle-closing spring in amanner whereby when the actuator is energized, it will begin overcomingthe force of said throttle-closing spring, permitting engineacceleration toward load speed and, after acceleration, the actuatorwill hold ineffective the throttle-closing spring, enabling regulationof the throttle for load speed operation, and

4. A load-responsive switching relay, responsive to load demand on theengine-generator set, and controlling the energization of the actuatorwhereby the actuator is energized from the initiation to the terminationof load demand, said actuator being de-energized from the termination tothe initiation of load demand.

The invention will be more readily understood by reference to theaccompanying drawings, in which Figure 1 illustrates diagrammatically aD. C. engine-generator set as used for welding application, with thewelding arc interrupted and the throttle-closing spring opposing thegovernors loading spring, thus effecting a slow (idling) speed. Figure 2illustrates an A. C. engine-generator set, with the load switch open andthe engine operating at slow (idling) speed, while Figure 3 is the samearrangement as in Figure 2, but the positions of the elements are thosewhen the load switch has been closed, and the force of thethrottle-closing spring is removed so that the engine is operating atthe higher governed speed to serve the load.

Referring again to the drawings, and particularly to Figure 1, numeral 1indicates an internal combustion engine, such as a gasoline engine,having a crankcase 2, and driving a D. C. welding generator 3 and anexciter generator 4. The exciter generator has a shunt field 5 and thisgenerator also energizes field 5 of the welding generator. The weldinggenerator also has a series field 5". Numeral 6 indicates the loadcircuit (which is depicted by a bold line), while numeral 7 representsthe welding electrode, and 8 the workpiece being welded. In this figure,the arc has not been struck.

The engine has a carburetor 21 and fuel intake pipe 20 connecting thecarburetor with the engine inlet. A conventional throttle (or throttlevalve) 22 is located in intake pipe 20, and is mounted on a pivot 23having fixed thereto the usual throttle arm or lever 24. Lever 24 has aflange 28, which may bear against an adjustable stop screw 25 to limitthe maximum closure of throttle 22. Said stop screw is carried bybracket 26 mounted on intake 20. A conventional mechanical governor(hereinafter referred to as the centrifugal governor) is indicatedgenerally as 10. The centrifugal operating mechanism thereof is wellknown, and is not illustrated, and such mechanism may be insidecrankcase 2, and is connected with governor arm 11 by rocker shaft 11'to exert a force on arm 11 which is proportionate to engine speed, andthis force urges arm 11 leftwardly in the drawings. This centrifugalforce is opposed by governor loading spring 12, and governor arm 11 isconnected with throttle arm 24 by a link 27. Loading spring 12 is ofsuch force that if it is opposed only by the centrifugal mechanism,throttle 22 will be regulated in a manner to maintain the predeterminedhigh operating speed that is necesary when the Weldinganc is in effect.An adjustment screw 15 enables adjustment of such predetermined highoperating speed. A

An electromagnetic actuator is indicated generally by numeral 30. It ismounted on an iron or steel angleshaped panel or bracket 32 which isrigidly attached to the engine, as by being clamped between intake pipe20 and the engine proper, as shown. Actuator 30 includes iron end framesor brackets 31 and 31 which, together with panel 32, provide thereturn'magnetic circuit of the actuator. Actuator 30 has a plunger 33,which slides within the usual tube 34 made of brass or other non- 27, togovernor arm 11. force is in direct opposition to the force of thegovernor loading spring 12. One end of spring 47 is carried -'by a fixedbracket 48, while the other end is connected to extension 46 of lever40, and may be set at different positions by means of notches 49, so asto apply more brief interruption of the welding arc.

therein, in which is slidably supported the free or extending end 45 ofa connecting link 43 which has its right end swivelly attached to theupper end of throttle arm .24. An adjustable collar 44 is affixcd tolink 43 and it delivers the thrust of lever 40 to throttle arm 24, inthe direction of closing of throttle 22. A spring '47, which may betermed a throttle-closing spring (or a forced-idle spring), urges lever40 rightwardly, thus transmitting the force of said spring, throughseveral elements including link 43, throttle arm 24, and link Saidthrottle-closing spring or less force in opposition to loading spring12. It will 'be apparent that if actuator winding 35 is sufficientlyenergized, lever 40 necessarily will be drawn back, as

indicated, to the broken line position, and that such :action willremove completely the force or effect of the series field so that aportion of the welding cur- .rent will flow through winding 51, to pulldown armature 52 and close relay switching contacts 53 and 54.

"When these contacts are closed, winding 35 is energized with currentfrom exciter generator 4, the shunt connection being through means ofwires 57, 58 and 59.

Relay 50 is shown as equipped with a copper delay ring 55 which assuresa slow break on the part of contacts 53 and 54, insuring some time delayto prevent de-energization of operating winding 35 during any very Inpractice, it is usual to provide more complex time-delay arrangements,so as to obtain a longer time-delay than is conveniently obtainable byuse of a delay ring but, here, the particular expedients foraccomplishing the time-delay form no part of the present invention and,therefore, a simple I form of time-delay is illustrated.

' The positions of the elements in Figure l are those-of governed slow(idling) speed operation. Winding 35 is not energized, hence theactuator is in ineffective position.

Spring 47 is shown connected in the second notch 49, under whichcondition the force of the spring is less than that of governor loadingspring 12, so that there is a certain remaining spring-biasing effectwhich, in combination with the force of the centrifugal mechanism '(notshown), will result in a governed idling speed of the engine. Throttle22 will be slightly advanced and retarded, as necessary, to maintain theuniform idling speed, and all of the elements connected therewith, in-

cluding lever 40, plunger 33, and link 43, will movejn' unison with thethrottle and governor.

If spring 47 were connected with the fourth (outermost) notch 49, theeffective force of spring 47 then would be greater, as for instance, tomaintain flange 28 of throttle arm 24 against stop screw 25. Thus, if

desired, throttle-closing spring 47 may be of sufiicient force to assurea quite slow idling speed, but spring 47 should not be so strong as tohold throttle 22 so forcefully closed that the initial force of actuator30 will be insuflicient to cause acceleration. It will be noted par- 4ticularly that the idling speed can be adjusted Whenever desired, byselecting a particular notch 49, and that this adjustment has no effecton the adjusted high operating engine speed which is separately adjustedby adjustment 15.

When welding is to be resumed, the operator touches electrode 7 toworkpiece 8, thus causing energization of winding 51 and effectingclosure of contacts 53 and 54, so that operating winding 35 of actuator30 will be energized immediately to the extent of whatever voltage isbeing produced at that moment by exciter generator 4. Assuming that theadjusted force of spring 47 has been selected to insure a fairly slowidling speed, the voltage of generator 4 will be much below that whichwill be in effect after acceleration, and the energization of winding 35will be weak. Even so, there is necessarily some degree of pull exertedby plunger 33, which is in opposition to the force of spring 47 and thusslightly increases the effective loading of the centrifugal governor.Throttle 22 must, therefore, be advanced to at least some slight extendwhich, in turn, increases speed which results in the plunger 33 exertingstill more force in opposition to that of throttle-closing spring 47.Engine acceleration therefore will build up quite rapidly and, at acertain point, the pull of plunger 33 will be suflicient to complete themovement of lever 40 to the indicated broken line position at whichcondition all of the effect of spring 47 is entirely removed. Winding 35now has become sufficiently energized so that actuator 30 is easilysufliciently powerful (via contact of plunger 33 with core 37) 'for thepurpose of holding spring 47 icompletelv ineffective.

Contacts 53 and 54 will remain closed while the welding arc isestablished as well as for a short time after breaking of the arc and,upon opening of these contacts, the operating Winding is de-energized,so that the force of spring 47 is released and this spring immediatelyopposes the force of loading spring 12 and thus closes the throttle tothe idling "speed basis, while at the same time restoring plunger 33 tothe illustrated extended position. It will be apparent that the idlingdevice of Figure 1 may be attached to the engine-generator set withoutany modification of centrifugal governor 10. Also, it will be apparentthat the particular arrangement and interconnection of thethrottle-closing spring, actuator plunger, and governed throttle system,are such that weak energization of the actuator, as obtainable by shuntconnection with one of the generators of the generator set, issuflicientto bring about the needed acceleration when the electricalload. is connected, which in the case of the .welding application iswhen the arc is struck.

.103, .the exciter as1tl4. Field may be common to both generators 103and 104, as is a popular practice in :small A. C. engine-generator sets.The load circuit represented by numeral 106 and shown by a bold line hasa switch 107 and a load 108. While a single switch and a single load areindicated in practice, the engine-generator set may-serve a number oflarge or small appliances at different times, each with its own switch.

The electromagnetic actuator of Figure 2 is indicated generally bynumeral 60, and includes iron end brackets 61, 61', plunger 63,operating winding 65, and 'a fixed core or stop=67, extending partlyinto the winding. An adjustable collar 66.is provided on the outer endof plunger 63. A simple form of throttle-closing spring is illustratedin Figure 2, and is indicated by numeral 47. The helical spring ismerely disposed around the extended portion of plunger 63, whereby itpresses .rightwardly against collar 66. The force of spring 47' 63 andhas a free end 73 slidably supported in flange 72 formed on throttle arm24. A collar 71 is affixed to link 70 to deliver the thrust. In Figure2, spring 47' is exerting suflicient force to close the throttleeffectively to a suitably slow (idling) speed basis. While spring 47 isconsiderably expanded in Figure 2, as compared with its condition inFigure 3, it will be understood that the effect of spring 47 is fairlyuniform at all times and that, if the spring were removed from theplunger to permit complete expansion, it would become, say, twice thelength of that occupied in Figure 2.

The load-responsive relay of Figure 2 is a conventional D. C.electromagnetic switching relay, and it is energized when current flowsin load circuit 106, by means of a current transformer 75 and rectifier78. Transformer 75 (which preferably may be a saturable transformer ofthe type disclosed in copending application Serial No. 53 3,128, filedon September 8, 1955, by William E. McFarland) has its coarse primarywinding in series with load circuit 106, and the stepped-up voltage ofthe secondary winding 77 passes through rectifier 78 and wires 79 and 80to thus energize the operating winding 51 whenever load switch 107 isclosed to initiate flow in the load circuit. This action pulls downarmature 52, to close and hold closed contacts 53 and 54. The closedcontacts complete the energization circuit of the actuating winding 65,current being fed from A. C. load generator 1&3, through wires 57, 58and 59. As in the case of Figure 1, the small initial energization ofthe actuator is sufiicient to establish the cumulative acceleration.When the generated voltage rises sufficiently, plunger 63 is pulledfully inwardly to the position indicated in Figure 3, and spring 47'then is ineffective, and governor will control the operation at thepredetermined load speed so long as the load circuit current flowcontinues.

There is a particular advantage in utilizing A. C. for energizingoperating winding 65. In the case of the socalled self-excited A. C.plants, as illustrated, which have only one field, the generated voltageinitially may drop to a quite low value when the connected load 1.08happens to be a large motor.

This would result in adversely weak energization of actuating winding65. By using A. C. energization of the winding, however, the wire sizeof winding 65 may be relatively coarse to obtain relatively forcefulinitial plunger pull, considering the collapse of generated voltage.Even though the winding is relatively coarse, it will not overheatduring the period of full speed operation, as frequency then is perhapsthree times higher than at idling speed operation which, together withthe closed magnetic circuit of the actuator, limits the currentconsumption of the actuator to a few watts.

In the condition outlined by Figure 3, the higher operating speed isalready in effect, and throttle 22 is well advanced, indicating at leasta medium size load 1.08. Governor It) will open the throttle still widerif more load is connected. As soon as load switch 107 is again opened,actuator 6th is ineffective in overcoming the effect of spring 47', andthe spring immediately closes the throttle for deceleration, whereuponthe positions of the elements designated by Figure 2 are again ineffect.

I claim:

1. In an idling device for an internal combustion enginegenerator setsupplying power to a load circuit, the en gine thereof having a governedthrottle system including a centrifugal governor connected to thethrottle, said governor having a loading spring of such force as toenable regulation of the throttle for maintaining predetermined loadspeed operation under varying load when said loading spring is unopposedby the hereinafter mentioned throttle-closing spring, the improvementcomprising a throttle-closing spring arranged when in effect, to opposethe force of said governor loading spring to effectively reduce thespring loading of said centrifugal governor and thereby enforce anidling speed, an electromagnetic actuator, energizable by generatedcurrent through shunt connection with a generator of saidengine-generator set, said actuator being connected to saidthrottle-closing spring in a manner whereby, when it is energized, itwill begin overcoming the force of said throttle-closing springpermitting engine acceleration toward predetermined load speed and,after acceleration, it holds ineffective said throttle-closing springenabling regulation of the throttle for load speed operation, and aswitching relay, responsive to load demand on said engine-generator setand constructed and arranged to control the energization of saidactuator whereby said actuator is energized from the initiation to thetermination of load demand and is deenergized from the termination tothe initiation of load demand.

2. An idling device according to claim 1 in which said actuator is aplunger electromagnet, and interconnecting means between saidthrottle-closing spring, plunger, and governed throttle system arrangedand constructed in a manner whereby, when said electromagnet isde-encrgized the throttle-closing spring will apply its force on saidgoverned-throttle system in opposition to said governor loading springand at the same time hold said plunger in extended position and, whensaid electromagnet is energized, the plunger will apply force on saidthrottle-closing spring to remove the force of said throttle-closingspring from operative effect upon said governed throttle system.

3. An idling device according to claim 2 in which said switching relayis an electromagnetic relay having normally-open contacts, and having anoperating winding in series with the load circuit, whereby said relay isresponsive upon initiation of load circuit current flow to close saidcontacts and thereby connect said actuator in shunt with a generator ofsaid engine-generator set.

4. An idling device according to claim 1, in which said engine-generatorset is an A. C. set including an A. C. load generator for supplyingpower to a load circuit, and in which said switching relay is anelectromagnetic relay having normally-open contacts and an operatingwinding energizable upon load circuit current flow to effect the closureof said contacts, said actuator being energized by shunt connection withsaid A. C. load generator when said normally open relay contacts areclosed.

References Cited in the file of this patent UNITED STATES PATENTS

